Rectal polyp 0.3cmx0.4cm biopsy may be malignant or benign. Rectal polyp 0.3cmx0.4cm, there exists both the possibility that it is a benign lesion such as hyperplastic polyp, adenomatous hyperplasia or inflammatory polyp, and the possibility that it is a malignant tumor. However, if it is a malignant tumor, generally speaking, the degree of malignancy is relatively low, usually after surgical resection can be cured. Because the size of intestinal polyps is not directly related to their true malignancy, even if the size of the polyp is very small, there may be the possibility of malignant lesions, but also in the case of very large polyps, there is the possibility of benign lesions. The main criterion for malignant lesions in clinical practice is still to rely on pathological biopsy to determine, which is the gold standard for checking benign and malignant tumors. Therefore, the size of the polyp can not be taken to determine the benign and malignant. When the patient appears 0.3×0.4cm rectal polyps, should actively cooperate with the doctor to do further examination, early diagnosis, early treatment.